L-Histidine is an essential amino acid that serves as a precursor for histamine, an important neurotransmitter and immune system mediator. It is involved in the synthesis of carnosine, a dipeptide that acts as an antioxidant and pH buffer in muscles. Histidine plays a crucial role in protein synthesis, tissue repair, and the maintenance of the myelin sheath that protects nerve cells. It is particularly important during periods of growth and recovery.